Let Me Show You Love
by RhythmWolf Rocky
Summary: Castiel has been helping Dean and Sam on a case, but when he is left behind at the motel they're crashing at, the angel is paid a visit by a very unwelcome guest. Casifer PWP for YellowEyedDemon4699.


_Let Me Show You Love_

 _Foreword_

For my dear friend **YellowEyedDemon4699** , who prompted me with a fluffy and smutty Casifer fic. I hope you like it!

This is my first ever Supernatural FanFiction and contains a CastielxLucifer pairing. Spoilers for everything up to and including season six; this is set at some point after Castiel's little Godstiel phase. Warnings of dubcon in the beginning. Basically PWP. You have been warned.

* * *

Castiel studied the photos, print-outs, and newspaper clippings pinned to the cheaply wallpapered wall of the grungy motel room. Sam and Dean had gone to interview some of the people involved, leaving Castiel alone. Since he wasn't entirely confident with his social skills, the angel had offered to stay and try to work out any kind of patterns in the information they had found. He crossed his arms over his chest, deep in thought.

The bass downbeat of massive wings distracted the angel and he turned around in time to see a tall figure land next to the window behind him. This new angel's back was to him, but Cas _knew_ who it was. He watched, frozen in shock and fear as the man went to close the curtains over the windows for privacy, his movements deliberate and unhurried.

"Working for the Winchesters I see," the man said in a deep, calm voice. "Really, little brother. I thought you better than that."

"Lucifer," Castiel hissed in his low, gravelly voice, unsheathing his angel blade, although from what he had heard of Gabriel's fate, he knew he couldn't stand a chance. "Why are you here? You're supposed to be locked up in the Cage."

The archangel scoffed as he turned lazily on his heel to face Cas. "A cage like that could never contain both Michael and myself there for long. Only one archangel in a cage at a time, and so it spat us out." He pondered that. "Or maybe just me. I don't know what happened to our brother dear."

Castiel watched him warily, studying the choice of vessel. "That's Nick," he said with sudden realization. "I thought that vessel was destroyed."

"On the contrary," Lucifer replied without hesitation. "I had a few friends keeping it warm for _when_ I returned."

He stepped forward, his corrupted red and black Grace blazing around him, lighting up the room and casting the shadow of his six great seraphim wings on the wall behind him. Castiel stood his ground, bracing himself, his own smaller, purer Grace glowing around him, his black wings unfurling.

Before he could do anything, however, Lucifer darted forward with the speed faster than that of a striking serpent, disarming Castiel with a flick of his wrist and shoving him back so he was pinned to the wall beside one of the beds. Castiel growled as he tried to break free, but froze as the cold tip of the blade pressed to the skin of his throat. Lucifer lifted the smaller angel up so his feet dangled helplessly. The archangel glared straight into Castiel's blue eyes, his own narrowed and dark with menace.

"I really missed you, you know," Lucifer breathed, his gaze drifting downwards to appreciate the angel's vessel. "Especially all of this. I'm glad to see you've kept your meat suit."

"No thanks to you," Castiel growled, squirming uncomfortably. "You destroyed it once before, remember?"

"Oh, but God brought you back," Lucifer drawled.

" _Something_ did."

" _God_ did," Lucifer insisted. "Because you're his favourite. Just like I was, once."

"I am nothing like you."

"Really now?" amusement played in the archangel's gaze. "Tell me, Castiel. What was it like being God for a day, hmm? You swallowed up the souls of Purgatory, am I right? And let's not forget _Team Free Will_. You and I share the same situation. Tell me again how you are nothing like me."

Castiel scowled. He didn't have to ask how Lucifer knew those things.

Omnipotence was a bitch.

"Don't worry, Castiel," Lucifer cooed, breaking Castiel's thoughts. " _I_ still love you. And I understand what you've been through and what you're going through. I'm here to help."

Castiel narrowed his blue eyes in suspicion. "Help? That wasn't what you offered the last time we talked like this. You wanted me to join you."

"But what's the point in fighting now?" Lucifer pointed out. "Michael is gone; I could have taken over the world at this point. But I didn't. Because I was worried about you."

The smaller angel relaxed ever so slightly and Lucifer removed the blade, but didn't let him down.

"That's it," the devil said encouragingly. "Let me show you just how much I care."

Without warning, Lucifer tossed Cas onto the bed next to them, pouncing on top before the angel knew what had happened. He turned Castiel over onto his belly, pressing his body flat against Castiel's back. The angel shuddered as he felt the devil's hard-on against the curve of his ass.

"Stop, this, Lucifer," Cas managed to growl from between clenched teeth. He tried to push the teller man off, but he proved far too strong.

"No way," Lucifer retorted, amusement in his voice. "I'll teach you to enjoy this." He lowered his voice as he whispered in Castiel's ear. "Maybe now that you're in a human vessel you'll learn a thing or two about how filthy humans can be."

He moved down to Castiel's neck, kissing the exposed skin and working his way down as he slowly, gracefully removed the angel's trench coat and dress shirt. He left the tie on pointedly as he eased it from the collar, pausing in his actions to toss the clothes aside.

At that moment, Castiel tried to wriggle away, clawing at the sheets, attempting to free his wings and fly away, but Lucifer knew better than that. He dug his fingernails into the space between Castiel's spine and shoulder blades, where his wings connected with his body, nearly ripping them out. Cas let out a cry of pain and went rigid in agony.

"I told you to enjoy it," Lucifer hissed. Impatient, he undid the angel's trousers, gathering his pants as well as he yanked them down to his knees, exposing his ass. Castiel whimpered at the cold air against his heated skin, burying his face in the sheets as he felt Lucifer's hands exploring down under.

The devil let out a wordless sound of appreciation as he found the angel's half-hard member. "Hmm, it seems you are enjoying it," Lucifer purred in approval, stroking Cas to full hardness. The angel tried to tell him to stop, but what came out were incoherent moans and cries.

Suddenly, the hand on his cock disappeared, and Cas let out a frustrated keen. "Please…" he groaned. He wasn't sure if he was asking Lucifer to stop or continue.

Lucifer undid his jeans with one hand, collecting pre-cum from Cas on the other and rubbing it against his tight entrance, making sure to prepare him well, not wanting to hurt him. Castiel gasped as he felt Lucifer's fingers slide into him, one by one, stretching him gently. They rubbed against a spot within him that had him rolling his hips back, chasing the delicious sensation. He could practically _hear_ the grin spreading across Lucifer's face.

"What would you like me to do, Cas?" Lucifer purred, leaning down to speak in the angel's ear as he brought his erection out, rubbing himself against the angel's ass.

Castiel groaned at the sensation. "Want you," he panted. "Inside. Please."

Lucifer chuckled, a deep, lusty sound that sent shivers down Castiel's spine. "We'll have to work on your begging," he said as he removed his fingers and replaced them with his cock, pushing in gently, sensually, trying his best not to hurt Cas. Lucifer wrapped his arms around the angel's naked torso, still fully clothed himself as he thrust into the angel beneath him.

Castiel groaned as Lucifer started to move, picking a fast and steady pace. He was gentle, not at all as brutal as Castiel had expected. The smaller man looked over his shoulder at Lucifer, drool dripping from his lips as he spoke.

"Want to face you," Castiel pleaded in between gasps. "Want to see Lucifer."

The devil was slightly taken aback, but he complied without complaint, turning Cas around so they were facing each other, his length still buried deep inside. The angel instantly wrapped his arms and legs around Lucifer, pulling him closer, his eyes screwed tightly shut as he chased the pleasure.

Lucifer faltered, stunned, before smiling tenderly and embracing Castiel back. He had wanted to fuck Castiel mercilessly, scar him and destroy his innocence, show him what the human body was capable of. Except that proved impossible to do.

This must be what humans called _making love_.

They took it slow, the air filled with Castiel's pleasured gasps and groans. He dragged his fingers down Lucifer's spine, nails digging into those invisible wings as he approached his climax, tossing his head back and crying out in ecstasy, his muscles clenching around Lucifer as he painted their chests in white. The devil growled at the pain in his back and the pleasure he felt as Castiel tightened unbearably. He thrust once more and came, his mouth open in a silent cry as he emptied himself deep inside.

Castiel fell back against the bed, dragging Lucifer down on top of him with a huff. The angel winced as Lucifer pulled out of him and rolled off to lie beside him, panting.

Lucifer let out an amused growl as he inspected his soiled shirt. "You made a mess, Cassie," he growled, looking at the angel in disappointment.

"Sorry," Cas panted back, looking drowsy in the afterglow.

"It's fine," Lucifer laughed, snapping his fingers and cleaning himself up. Castiel growled at that.

"What about me?"

"You look prettier naked," the devil stated matter-of-factly. He rolled to his side, admiring the view and placed an arm around Cas, but the angel grabbed his wrist and pushed it back, propping himself up onto his elbows and wriggling closer to Lucifer, nuzzling into the devil's clothed chest.

"You're just hoping for seconds," Castiel accused, glaring up into Lucifer's eyes.

A lusty smirk crept onto Lucifer's face as he placed a hand on Castiel's head, pushing him lower.

"Maybe I am~"

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 _Afterword_

Depending on the reviews I get, I may or may not add in a round two... :)


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